Field of the Invention
The present invention relates to a dispenser and more particularly to an improved dispenser for fluent masses such as toothpaste, lotions, semi-solids and chemicals, and the like, in which the dispenser includes a collapsible pouch containing the material to be dispensed.
It is well known in the prior art to provide what is known as a bag-in-can type of dispenser, the latter also sometimes referred to as barrier packages. Typically, these products include an inner collapsible tubular bag-like inner container which holds the material to be dispensed, usually a relatively easily dispensible material of the type normally dispensed from an aerosol type of container. The power needed to dispense the material within the inner container is normally provided by a gaseous propellant such as Freon gas or a hydrocarbon or mixture of hydrocarbon gases, initially in liquid form. The outer container is structured as an aerosol dispenser with the usual valve and, in manufacture, the assembly is normally pressurized above ambient pressure from the bottom and plugged in the bottom with a seal, usually a rubber plug.
The interior of such devices may vary. In one case, a relatively rigid dip tube having perforations along the length thereof is used so that the material is discharged through the tube to the can valve, the above atmospheric gas pressure surrounding the inner flexible bag being operative to force the contents into the dip tube and out the valve. In another form, the inner container is pleated, i.e., accordion folded, and the above atmosphere gas pressure operates to compress the pleated inner container. In the latter system, depending upon the viscosity of the material being packaged, it is sometimes necessary to spin the assembly during filling of the inner container in order to assure that there are no air pockets in the inner pleated container. In some variations, the inner bag was pleated axially rather than radially.
Other aerosol type containers use a plastic float or piston which separates the interior of the outer can into two chambers, the bottom being a pressurized gas or initially liquid propellant gas and the side opposite the gas being the material to be dispensed, sometimes a rather viscous material. In this type of dispenser, it is usually necessary to provide a seamless can body in which the walls are essentially truly parallel in order to effect a seal along the periphery of the float or piston member.
In other variants, the inner bag is pressurized with the gas while the contents to be dispensed are located in the region between the inner bag and the inside wall of the outer can body. Such an arrangement, however required a much larger propellant charge than in the other systems mentioned.
In an attempt to avoid the use of aerosol containers, due to the ecology problem with Freon gases and the potential flammability of hydrocarbon gas propellants, "pressurized" dispensers were used. In a typical system of this type, a double bladder was used inside of an outer container to dispense the contents of the material within the bladder, the latter exerting a constant pressure on the contents, to discharge the same, as it returns to is initial shape.
Other forms of dispensers are those shown and described in U.S. Pat. Nos. 3,088,636; 3,268,123, 3,255,935; 3,768,705; and 3,870,200. In general, these devices are pump type dispensers in which the material to be dispensed is a fluent mass such as toothpaste. The outer container, fabricated of plastic, includes essentially parallel side walls and of a sufficient thickness to be relatively rigid. Pumping was achieved through a pump chamber cooperating with the contents chamber such that as the pump was actuated material in the chamber was dispensed, and material from the contents chamber entered the pump chamber. The bottom end of the pump chamber was closed by a piston, movable axially along the length of the contents chamber, each time the pump was actuated. Thus, the walls of the pump chamber were parallel, smooth and of sufficient thickness to resist deformation during a pumping action. Further, the piston or float was structured to permit movement in one direction while resisting movement in the other direction, while providing a seal to the cooperating wall along the length of the wall. The contents were in direct contact with the wall and the piston thus necessitating that the material of the wall and piston be compatible with the contents.
The dispensers of the above patents operate quite well, especially for relatively viscous materials such as toothpaste, lotions and other similar materials as well as free flowing liquid materials, but are relatively expensive for products which are sold in large volumes and in which the costs of packaging are significant considerations. Thus, for example, a plastic body which is of sufficient thickness to be rigid is more expensive than essentially the same body of a material of thinner cross-section, merely in terms of material costs. It is also true that a reduction in wall dimension allows faster molding cycles. The need to provide controlled geometry due to the need for smooth and parallel interior walls tends to increase the costs of the tooling and part production, but also restricts the package design to a generally cylindrical body. Further, the need to fashion a float or piston member which seals to the interior of the cylindrical body also tends to require mating parts of relatively high precision. Also a factor is the need to provide a float or piston capable of effectively sealing to the side wall and which is moveable in one direction, but which resists movement in the other direction. Since the packaged material is in direct contact with the wall of the chamber within which it is contained, the barrier qualities of the wall may not be as desirable as might be needed for certain types of products.
It is thus an object of the present invention to provide a relatively simple pump type dispenser for fluent materials which is relatively simple in design, effective in operation and which does not include a movable piston or float assembly.
It is also an object of this invention to provide a dispenser for fluent materials of the type to be described in which ambient pressure is used as the power source in a pump type dispenser in which the material to be dispensed is contained within a flexible and collapsible bag-like member and wherein ambient pressure effects passage of the dispensed material to a pump chamber.
Another object of this invention is the provision of an improved dispenser for fluent materials in which the material is discharged from a pump chamber which in turn is filled from a flexible bag-like member, substantially free of trapped air or compressible gases, and contained within a body member and in which the walls of the bag are spaced from the wall of the body member to form an air gap, at essentially ambient pressure, in order to dispense material in the bag and to increase the barrier qualities of the overall package.